PhatBob that actually happened to me just a week or so ago. Thing just exploded. May have been not balanced just right but dang that was dangerous. Also was working on a 125 when i guess it backfired or something and the prop shot 50ft. across the yard. I suppose that is why you check them there bolts and nuts. Used a metal detector and acutally found the prop nuts. Just glad i was behind the prop at the time.